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From: Jan Glauber <jan.glauber@de.ibm.com>
To: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>,
	akpm@osdl.org, mingo@elte.hu, ak@suse.de, schwidefsky@de.ibm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [patch] i386/x86_64: smp_call_function locking inconsistency
Date: Fri, 09 Feb 2007 13:57:18 +0100	[thread overview]
Message-ID: <1171025838.5349.14.camel@localhost.localdomain> (raw)
In-Reply-To: <20070209084221.GA8259@osiris.boeblingen.de.ibm.com>

On Fri, 2007-02-09 at 09:42 +0100, Heiko Carstens wrote:
> I just want to avoid that s390 has different semantics for
> smp_call_functiom*() than any other architecture. But then again it
> will probably not hurt since we allow more.
> Another thing that comes into my mind is smp_call_function together
> with cpu hotplug. Who is responsible that preemption and with that
> cpu hotplug is disabled?
> Is it the caller or smp_call_function itself?

I think the caller must disable preemption since smp_call_function()
means "do something on all but the current cpu". If the preempt_disable
would happen only in smp_call_function() it could already be running on
a different cpu, which is not what the caller wants.

If preemption must be disabled before smp_call_function() we should have
the same semantics for all smp_call_function_* variants.

Jan


  reply	other threads:[~2007-02-09 12:58 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-08 20:32 Heiko Carstens
2007-02-08 20:43 ` David Miller
2007-02-09  8:42   ` Heiko Carstens
2007-02-09 12:57     ` Jan Glauber [this message]
2007-06-07 14:07       ` Satyam Sharma
2007-06-07 16:27         ` Heiko Carstens
2007-06-07 16:54           ` Satyam Sharma
2007-06-07 17:18             ` Satyam Sharma
2007-06-07 17:22               ` Avi Kivity
2007-06-07 17:33                 ` Satyam Sharma
2007-06-10  7:38                   ` Avi Kivity
2007-06-08 19:43             ` Andi Kleen
2007-06-08 19:42         ` Andi Kleen
2007-02-09  7:40 ` Andi Kleen

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